The present invention relates generally to a clip for releasable, push-to-connect fittings for tubing, and more particularly to such a clip having a shroud portion for controlling the release of the tubing end from the fitting.
Tube fittings of a manual "push-to-connect" type are widely employed in a variety of pneumatic, hydraulic, and other fluid transport applications utilizing plastic or metal tubing. Also known as "push-in" or "quick-release" fittings, these fittings have been adapted for use as connectors with many different tubing types including polyurethane (PU), polytetrafluoroethylene (PTFE), fluorinate ethylene polypropylene (FEP), perfluoroalkoxy resin (PFA), polyethylene (PE), polypropylene (PP), rigid and flexible nylon, acrylonitrile-butadiene-styrene (ABS) copolymer, copper, and brass. Typical applications include commercial and residential water filtration and purification, such as in carbon or filament-based water filtration canisters or in reverse osmosis systems, water softening, beverage distribution, as well as industrial pneumatics and chemical processing.
In basic construction, these fittings, which may be configured as couplings, connectors, unions, adapters, tees, elbows, or caps, involve a generally annular body having throughbore which extends between a forward, open first end and, typically, a rearward, threaded second end. An expandable collet is slidably received within a gland of the open end of the body as extending between an external forward end and an internal rearward end which is formed of a plurality of circumferential, arcuate sections. Each of these resilient segments extends between a forward proximal end and a rearward distal end formed as having a radially outwardly facing shoulder of an enlarged outer diameter and a wedge-shaped, radially inwardly facing grip edge. These grip edges, in turn, are formed by the intersection of a forward and a rearward presenting inclined surface, the forward surface functioning as a camming surface effecting the radial outward expansion of the collet sections allowing for the insertion of a distal tubing end pushed through the collet from the open forward end of the body. A rearwardly-inclined ramp surface typically is operatively associated with the collet shoulders as integrally-formed within the internal surface of the body throughbore or gland at a position forward of the collet segment distal ends, or as separately provided as formed within the internal surface of a retaining ring interposed between the outer circumferential surface of the collet and the inner circumferential surface of the open forward end of the body. An o-ring or other seal member may be interposed between the rearward end of the collet and a forwardly presenting end wall of the body gland for effecting a fluid-tight engagement with the outer wall of the tubing and the inner wall of the body.
For assembly, as the tubing is inserted into the fitting, the distal end of the tubing first is passed through the grip edges of the collet, the segments of which expand to resiliently capture and hold the outer diameter of the tubing, and then through the o-ring which provides a leak-proof seal against the tubing outer wall. The advancement of the tubing into the open end of the fitting is continued until positively stopped by the forwardly presenting end wall of the body gland. Upon the pressurization of the tubing, or as the tubing is pulled or otherwise placed in tension by a generally forwardly directed axial force, the collet is moved slidably forwardly with the tubing. This movement is delimited, however, by the shoulders of the collet sections being made to abuttingly contact the ramp surface of the body in an force transmitting engagement applying a radially-inwardly directed force to the collet segments and the grip edges thereof. In this way, the grip of the collet thereby is energized to compressively tighten about the outer wall of the tubing preventing the removal of the tubing from the fitting.
For disassembly, the tubing may be released from the fitting by manually repositioning and holding the collet at its rearward-most axial position, typically with the forward end of the collet being abutted against the first end of the body. In such position, the collet segments are de-energized and again may be expanded to release the tubing. In this regard, the external rearward end of the collet may be configured as an annular collar which may pushed axially inwardly for advancing the collet and tubing within the body. The measure between the rearward-most and the forward-most position of the collet is known the art as the "collet rise" or "travel," and is the linear distance which the collet moves relative to the body. Generally, it is preferred to minimize this distance as extended collet travel increases the space necessary to install the fitting and otherwise is known to increase the potential for collet damage.
Representative push-in fittings of the type herein involved are described in U.S. Pat. Nos. 3,653,689; 3,999,783; 4,005,883; 4,009,896; 4,059,295; 4,111,575; 4,178,023; 4,302,036; 4,335,908; 4,573,716; 4,600,223; 4,606,783; 4,637,636; 4,645,246; 4,650,529; 4,657,286; 4,722,560; 4,770,445; 4,804,213; 4,884,829; 4,923,220; 4,946,213; 5,046,763; 5,230,539; 5,303,963; 5,314,216; 5,330,235; 5,370,423; 5,401,064; 5,437,483; 5,439,258; 5,443,289; 5,468,027; 5,511,830; 5,607,193; 5,024,468; and in UK Patent No. 1,602,077. Commercial fittings of such type are marketed by: John Guest, Berkshire, U.K.; Mazzer Industries, Rochester, N.Y., under the name "Insta-Brass.TM.;" Norgren of Lichfield Staffordshire, England, under the name "Pneufits.TM.;" Alkon of Diadema, Brazil; Imperial Eastman of Chicago, Ill., under the name "OmegaFlo.TM.;" Camozzi, Brescia, Italy; Weatherhead, Toledo, Ohio, under the name "Push-Connect.TM.;" Legris Industries, Rennes, France, under the name "LF 3000.TM.;" SMC Pneumatics Inc., Indianapolis, Ind., under the name "One Touch;" Brass Products Division of Parker-Hannifin Corp., Otsego, Mich., under the name "Prestomatic.TM.," which fitting is further described in the commonly-assigned co-pending application U.S. Ser. No. 08/656,743, filed Jun. 3, 1996; and Parflex Division of Parker-Hannifin Corp., Ravenna, Ohio, under the name "Tru-Seal.TM.," which fitting is further described in U.S. Pat. No. 5,584,513.
Another fitting of the push-in type includes a grab ring formed of a plurality of resilient fingers for gripping the tubing, and a release sleeve which is slidably interposable between the fingers and the tubing outer wall for releasing the tubing from the fitting. Push-in fittings exemplary of this design include those marketed by the Brass Products Division of Parker-Hannifin Corp. under the name Prestolok, by Nycoil of Fanwood, N.J., under the name "Polymatic.RTM.," and by Pisco Products of Okaya City, Japan.
To control the disconnection of the tubing, a spring-type locking clip conventionally is employed. One such clip, shown in commonly-assigned U.S. Pat. No. 5,584,513, is of a resiliently expandable "horseshoe" or "omega" shape configured to be received over the collet as interposed between the external forward end thereof and the corresponding end of the fitting body. Typically, theses clips are designed to be "wedged" between the collet and the fitting body such that the collet is urged to its energized, forward-most position. Similarly functioning locking clips are shown in U.S. Pat. Nos. 4,005,883; 4,009,896; 4,059,295; 4,884,829; 5,330,235; and 5,437,483.
Alternatively, locking covers are provided to prevent the collet from being accidentally or otherwise unintentionally moved to is rearward-most, de-energized position. As is shown, for example, in U.S. Pat. No. 4,573,716, such caps include cylindrical side walls that extend over the collet into a mechanical or other engagement with the fitting body, and an end wall having a central aperture through which tubing is allowed to pass. Other representative covers of like construction are shown in U.S. Pat. Nos. 4,573,716; 4,923,220; 5,046,763; and 5,468,027, and in UK Patent No. 1,602,077.
As facilitating the assembly of fluid systems and obviating the need for tools or special skills to effect the tubing connections, the fittings of the above-described push-in types have represented an important advancement in the field of fluid connectors. However, as the applications for these fittings continues to grow, the concern for safety remains. Indeed, in certain applications, such as residential and commercial water purification, softening, and filtration systems, the use of these fittings is subject to compliance with industry standards and governmental regulations. It therefore will be appreciated that improvements in releasable, push-in tube fittings, and particularly in controlling the release of the tubing therefrom, would be well-received by industry.